1. Field of the Invention
The present invention relates to motor vehicle fuel systems.
2. Description of the Related Art
In the control of fuel delivery to a motor vehicle engine, knowledge of the temperature of the fuel being delivered can frequently be advantageous. An "electronic returnless" fuel system is one fuel system in which such knowledge of fuel temperature can be advantageous. In an "electronic returnless" fuel system, the speed of the fuel pump is feedback-controlled such that exactly the required amount of fuel is delivered to the engine. Thus, the conventional return fuel line to the fuel tank can be eliminated. In such an "electronic returnless" fuel system, the ability to control fuel pump speed (and therefore fuel pressure) can be used to advantage to prevent fuel vaporization in the fuel rail of the engine. If such vaporization is impending, the fuel pressure can be increased as a countermeasure. Reducing fuel vaporization can improve engine starting and driveability.
However, to provide such a countermeasure, the temperature of the fuel in the fuel rail should preferably be known. Of course, the prior art recognizes that a fuel temperature sensor can be used to sense fuel temperature. But, with the ever-increasing pressures for motor vehicle cost efficiency, an alternative means for sensing fuel temperature which does not require a dedicated sensor can provide substantial advantages over the prior art.